/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jasper.tagplugins.jstl.core;

import org.apache.jasper.compiler.tagplugin.TagPlugin;
import org.apache.jasper.compiler.tagplugin.TagPluginContext;

public class Redirect implements TagPlugin {

	public void doTag(TagPluginContext ctxt) {

		// flag for the existence of the "context"
		boolean hasContext = ctxt.isAttributeSpecified("context");

		// names of the temp variables
		String urlName = ctxt.getTemporaryVariableName();
		String contextName = ctxt.getTemporaryVariableName();
		String baseUrlName = ctxt.getTemporaryVariableName();
		String resultName = ctxt.getTemporaryVariableName();
		String responseName = ctxt.getTemporaryVariableName();

		// get context
		ctxt.generateJavaSource("String " + contextName + " = null;");
		if (hasContext) {
			ctxt.generateJavaSource(contextName + " = ");
			ctxt.generateAttribute("context");
			ctxt.generateJavaSource(";");
		}

		// get the url
		ctxt.generateJavaSource("String " + urlName + " = ");
		ctxt.generateAttribute("url");
		ctxt.generateJavaSource(";");

		// get the raw url according to "url" and "context"
		ctxt.generateJavaSource("String " + baseUrlName + " = "
				+ "org.apache.jasper.tagplugins.jstl.Util.resolveUrl("
				+ urlName + ", " + contextName + ", pageContext);");
		ctxt.generateJavaSource("pageContext.setAttribute"
				+ "(\"url_without_param\", " + baseUrlName + ");");

		// add params
		ctxt.generateBody();

		ctxt.generateJavaSource("String " + resultName + " = "
				+ "(String)pageContext.getAttribute(\"url_without_param\");");
		ctxt.generateJavaSource("pageContext.removeAttribute"
				+ "(\"url_without_param\");");

		// get the response object
		ctxt.generateJavaSource("HttpServletResponse " + responseName + " = "
				+ "((HttpServletResponse) pageContext.getResponse());");

		// if the url is relative, encode it
		ctxt
				.generateJavaSource("if(!org.apache.jasper.tagplugins.jstl.Util.isAbsoluteUrl("
						+ resultName + ")){");
		ctxt.generateJavaSource("    " + resultName + " = " + responseName
				+ ".encodeRedirectURL(" + resultName + ");");
		ctxt.generateJavaSource("}");

		// do redirect
		ctxt.generateJavaSource("try{");
		ctxt.generateJavaSource("    " + responseName + ".sendRedirect("
				+ resultName + ");");
		ctxt.generateJavaSource("}catch(java.io.IOException ex){");
		ctxt
				.generateJavaSource("    throw new JspTagException(ex.toString(), ex);");
		ctxt.generateJavaSource("}");
	}

}
